This invention relates to a yarn winding mechanism in a spinning unit of a spinning machine, which is provided with a device for compensating changes in yarn tension due to cone winding by the winding mechanism.
In the yarn winding mechanism, generally, the yarn is traversely wound onto a suitable bobbin to obtain a desirable cone cheese, and therefore the winding mechanism must be provided with a device for compensation for changes in yarn tension caused by both the cone winding and the traverse. Furthermore, in the case of an open end spinning unit wherein a yarn is positively discharged out of a spinning chamber, a yarn number is apt to be affected by a speed at which the yarn is taken out of the spinning chamber. Therefore, when it is desired to produce a uniform number of yarn, the yarn taking-out speed should be maintained constant, otherwise a poor quality of yarn will be produced. To ensure the yarn being traversely wound at the constant speed, each open end spinning unit in the open end spinning machine has a pair of yarn taking-out rollers disposed between the winding bobbin and the yarn discharge tube. The yarn taking-out rollers firmly hold the yarn therebetween and take it out of the yarn discharge tube at the constant speed.
In such a spinning unit, on occurrence of a yarn breakage during the spinning operation, a yarn breakage detecting device detects the yarn breakage and provides a signal to stop a supply of fibers into the open end spinning chamber. A cut end of yarn is wound up onto the cone cheese. When it is desired to carry out the yarn ending, the cone cheese is relieved from a drive roll and thereafter the yarn cut end is wound off until it is led to the outlet of the yarn discharge tube without passing between the yarn taking-out rollers, whereupon the cut end is sucked into the rotary spinning chamber and reaches on a fiber collecting surface thereof, where it is connected with the fibers supplied again into the spinning chamber. In order that the yarn is taken out of the spinning chamber at the constant speed, the yarn must be placed between the yarn taking-out rollers without error immediately after completion of the yarn ending. However, this requirement has not been satisfied with the prior art winding mechanisms.
It is accordingly a primary object of this invention to provide a yarn winding mechanism in a spinning unit which is capable of placing a yarn between a pair of yarn taking-out rollers with no error immediately after completion of yarn ending.